Athletes use extracts of Cissus quadrangularis to help joint injuries mend more quickly. If the collagen producing cells react in the same way as the bone cells that endocrinologists at the University of Madras used in their experiments, this may throw light on how the extracts work: they boost IGF-1 production.

Little is known, however, about how Cissus quadrangularis works. Content analyses of the steroid compounds have prompted the usual speculations about androgenic and oestrogenic components. Another theory is that antioxidants in Cissus inhibit breakdown processes.

The researchers at the University of Madras took a different approach. They put human osteoblasts – the SaPS-2 cells responsible for bone formation – into test tubes with a fluid containing an alcohol extract of Cissus quadrangularis. The researchers observed that the extract made the cells produce more IGF-1 [structural formula shown here], and more IGF-1 receptors [IGF1R]. IGF-1 is one of the most powerful growth factors known to science.

The extract also boosted the synthesis of IGFBP3. This is a binding protein that attaches itself to IGF-1 and prevents enzymes from breaking down the hormone. It doesn't affect IGF-1 from functioning however.

The researchers cannot say which compounds in the extracts cause these effects on IGF-1. They do indicate that phenols in prunes have the same effect. [Bone. 2006 Dec;39(6):1331-42.]